A weblog for professionals in electrical, electronic, mechanical and software engineering with content provided by the members of the Long Island Consultant's Network.

October 2011

October 29, 2011

A power amplifier for CDMA service is described at http://www.maxim-ic.com/app-notes/index.mvp/id/456 where we read of performance that is characterized at an output power of +28 dBm, slightly more than 630.9 mW.

At http://www.datasheetcatalog.org/datasheet2/6/0esegl2hrtjs4ohlwyih6gc8p8ky.pdf , we find amplifier maximum output power specifications for W-CDMA service of +28.5 dBm which, slightly more than 707.9 mW.

At http://www.msnbc.msn.com/id/43456368/ns/business-us_business/t/new-elongated-boeing---debuts-paris/ , we read that Boeing has just introduced their new 747-8 jumbo jet. We also read that this aircraft will have 467 seats. The Airbus A380 can seat even more passengers, but let's just call this a jumbo jet seating capacity of 400+.

October 22, 2011

For about 2 years now, Toyota has been hinting at a plug-in hybrid electric vehicle (PHEV) version of the PRIUS. Now they are releasing more details that reflect a shift in how Toyota is approaching the hybrid vehicle.

The PRIUS is without doubt the most successful hybrid vehicle in the world, so extreme caution by Toyota is warranted. But the surprising thing is that they are reducing the electric only range AND they do NOT call it a PHEV-----only a PHV downplaying the electric drive portion. WHY?

October 20, 2011

When a transformer winding is driven from an amplifier whose DC voltage level must be blocked from the driven winding and high isolation requirements are an issue, it is better from a cross-coupling suppression standpoint to put that capacitor in the low side of the transformer winding instead of in the high side.

October 18, 2011

Rail voltage responses to current pulses are analyzed using recursive differential equations and two different current pulse models on the worst case assumption that passive decoupling effects of bypass capacitors are all that we have working in our favor..

It is shown in this particular case that rail voltage excursions in response to current pulses of 3 nSec rise and fall times do not exceed 40 mV per Ampere of peak pulse current.

October 15, 2011

About 2+ years ago I wrote a BLOG for the LICN entitled “HYBRID-HYBRID?” It appeared July 22, 2009. It specifically addresses the thought of using hydraulic engineering to improve the efficiency of HEAVY vehicles such as garbage trucks. That technology is in use and several truck and bus companies are using technology provided by Eaton Industries and others.

But what about the ordinary car OR more specifically the SUV/VAN? A number of experimenters are trying to do the hybrid job using hydraulics and the basic reason is that it does appear the approach is fundamentally simpler and the equipment fairly straightforward. Hydraulic hybrids operate basically the same way as gasoline-electric hybrids, but they use a motor-pump instead of an electric motor generator---and an accumulator rather than a battery pack. The motor/pump is directly comparable to a PMSM mot/gen---just more efficient. The accumulator is more comparable to a SuperCap and IS more efficient than a battery. When the driver slows down or brakes, the pump forces the hydraulic fluid out of a low-pressure reservoir into a high-pressure tank. To accelerate, the fluid is forced back to the low-pressure tank through the pump/motor, which applies torque to the wheels. The claim is the regenerative braking system, can put as much as 80 percent of the braking energy back to the wheel which is better than current gasoline-electric hybrids.

October 11, 2011

You can be confronted with some dependent variable that varies versus some independent variable where that variation just happens to be of the greatest interest when the independent variable is somewhere in the middle of a numerical range.

A graphic image of the relationship between the two variables may benefit if the x-axis of the presentation is given a bidirectional logarithmic compression along the lines (no pun intended) of the following examples.

Here, we look at x-axis plots of a variable from zero to 100 with the center value equaling 50. Vertical rises are shown upward at increments of 10:

The larger you make the coefficient K2, the more expanded the x-axis becomes in the center and the more compressed at each end. Coefficient K1 then needs to be tailored for the appropriate width.

October 08, 2011

OHM’S LAW FOR HYBRIDS: BER or regenerative braking is a direct way of recovering AND reusing brake energy normally wasted in heating the brake linings. The law simply states the motor must be sized upon braking requirement and acceleration desires. To make the greatest use of recovering the energy upon braking, the motor battery combination ALONE must be able to provide the acceleration.

MEETING THE GOVERNMENT FUTURE REQUIREMENTS---HOW?Jul 29, 2011 President Barack Obama delivered remarks on fuel efficiency standards for 2017-2025 model year cars and light-duty trucks during an event at the White House with the pontificating announcement of 54.4mpg composite(?). The puzzling thing is it didn’t really clarify anything. In particular it puts NO emphasis in improving LOCAL driving mileage-----apparently in the grand scheme it is insignificant in the government’s mind. SO no help can be expected in the development of an affordable SUV/VAN capable of 20—25 mpg for general urban usage. TOO bad! SUVs and VANs are the most popular vehicles with young families and 80% of the driving is LOCAL.